Modular photovoltaic element for building roofs

ABSTRACT

A modular photovoltaic element for building roofs comprising:
         a lower hollow structural part of plastic material,   an upper convex cover element of material transparent to sunlight and fixed to said hollow part,   at least one photovoltaic cell mounted on a support and housed in a cavity defined by said hollow part and said convex cover element,   an integrated current for controlling the operation of said element,   a compartment which is separate from the cavity housing said photovoltaic cell, and which houses means for electrical connection to the adjacent modular element of the same row, partially superposed to cover said compartment,   connection cables joined to watertight connectors positioned on the surmounting portions of adjacent hollow parts of one and the same row, said connectors being connected to said photovoltaic cell and to said integrated circuit,   first mechanical means for connecting said cover element to said hollow part,   second mechanical means for connecting said hollow part to the hollow part of adjacent elements of the same row, and   a base member adapted to connect said hollow part to the underlying roof.

FIELD OF THE INVENTION

The present invention relates to a modular photovoltaic element for building roofs.

BACKGROUND OF THE INVENTION

Modular elements of clay material are known for forming building roofs. They are commonly known as plain tiles or single-lap tiles depending on their shape. The present description uses exclusively the term “tile”, even though the invention also relates to modular elements different from plain tiles.

For some time, photovoltaic modules, known as photovoltaic tiles, have been proposed as a replacement for traditional clay tiles. Photovoltaic tiles do not possess the traditional tile shape, are often incompatible with the connections required between one tile and the next, and are incompatible with the need for a surface transparent to the sun's rays and the ability to define, with the remaining part of the tile, a chamber for housing the photovoltaic cells. Consequently the roofs made with these photovoltaic tiles have lost the appearance of classical roofs and integrate unsatisfactorily within an environmental context.

BRIEF SUMMARY OF THE INVENTION

An object of the invention is to eliminate these drawbacks by providing photovoltaic tiles which are totally similar externally to classical tiles, but, which on installation, are able to establish the necessary connections with the adjacent tiles and/or with conductors for transferring the electrical energy generated thereby to the outside.

This and other objects which will be apparent from the ensuing description are attained, according to the invention, by applicant's unique modular photovoltaic element for building roofs.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the present invention is further clarified hereinafter with reference to the accompanying drawings, in which:

FIG. 1 is an exploded perspective view of a modular photovoltaic element according to the invention,

FIG. 2 is a perspective view of its base seen from below,

FIG. 3 is a perspective view of its lower support part seen from above,

FIG. 4 is a perspective view thereof with a positionable support for the photovoltaic cells applied,

FIG. 5 is a perspective view of the support for the photovoltaic cells,

FIG. 6 is a perspective view thereof seen from below,

FIG. 7 is a detailed perspective view of the connection between two tiles of the same row, and

FIG. 8 is an enlarged partial cross-sectional view through the tile cover element of transparent material.

DETAILED DESCRIPTION OF THE INVENTION

As can be seen from the figures, the tile of the invention comprises three basic elements, consisting of a base 2 for fixing to the structural element of the underlying building roof (not shown), a tile lower part 4 and an upper convex element 6. Convex element 6 defines with the underlying lower part 4, a chamber for receiving the tile functional elements, and in particular, the photovoltaic cells 8.

The base 2 is made of molded plastic and is shaped as a tray, with the two longitudinal sidepieces 10 projecting upwards, and from which two appendices 12 extend downwards for fixing the base to the roof structural elements, preferably by screws.

Each appendix 12 has its end bent outwards to define a portion shaped in a manner complementary to that of the other appendix (see FIG. 2), to facilitate connection to the corresponding tile of the adjacent row, the term “row” meaning the succession of tiles extending along the sloping line from the roof ridge.

The bent end of all the appendices 12 includes a hole 13 which, when the appendices 12 are insertedly engaged, faces the hole of the corresponding appendix to enable the bases 2 of two adjacent tiles to be fixed together by a single screw, thereby ensuring regular mutual positioning of the tiles.

Each upwardly projecting edge 10 of the base 2 also comprises seats 14 to be engaged by teeth 16 of the overlying tile lower part 4, and by centering appendices 18 of adjacent bases 2 of the same row.

The lower part 4 of the tile of the invention is also made of molded plastic and presents a perimetral edge similar to the frusto-conical shape of a traditional tile. However, in contrast thereto part 4 comprises, in its central part, a sunken portion forming the lower portion of a chamber to receive the photovoltaic cells 8 and provided with aeration appendices 19. The photovoltaic cells 8 can be directly fixed to the lower part 4, or can be mounted on a support 20 hinged to part 4, to enable the inclination of the support to part 4 to be adjusted, both transversely and longitudinally, to optimise exposure of the photovoltaic cells to the sunlight. This inclination adjustment can be continuous, or stepwise.

Seats 24 are provided along the longitudinal edges of the part 4, to be engaged by teeth 26 provided in the transparent cover element 6.

The cavity of the part 4 does not extend for the entire length of the part but leaves two end bands free to lie between the parts 4 of adjacent tiles pertaining to the same row.

More specifically, the downstream end of the part 4, i.e. that end which when installed lies at a lower level, projects beyond the corresponding end of the base 2 and comprises an appendix 28 housing a watertight male connector 30 for electrical connection to the downstream tile pertaining to the same row.

The upstream end of the part 4 comprises a cavity 32 housing a watertight female connector 34 for connection to the upstream tile pertaining to the same row.

The contacts of the male connector 30 and female connector 34 are intended to connect to cables 36 and 38 connected to a watertight integrated circuit 40 for controlling tile operation, other contacts being provided to connect to the female connector 34 and male connector 30 of adjacent tiles, as described hereinafter.

Connection strips 22 already connected to the photovoltaic cells 8 are connected to the integrated circuit 40 via cables housed in watertight sheaths.

Two smaller cavities 42 are provided to the side of the cavity 32 in the part 4 to cooperate with appendices 44 of the part 4 of the adjacent tile pertaining to the same row, to provide correct mutual mechanical connection.

The cover element 6 is made of transparent material and is of frusto-conical shape matching the frusto-conical shape of the edge of the part 4, to give the tile the shape of a traditional tile. For mechanical strength reasons the cover element 6 presents a plurality of lower stiffening ribs and also a plurality of teeth 26 for engaging in the seats 24 of the part 4, to fix the cover element 6 to the part 4. Following this fixing, the part 4 defines, with the cover element 6, a chamber for housing the photovoltaic cells and which is made impermeable to water by interposing a continuous gasket 46 between the two.

The lower surface of the cover element 6 also defines a plurality of lenses 48 the purpose of which is to concentrate the sun's rays onto smaller portions of the photovoltaic cells (see FIG. 6) in order to reduce the quantity of photosensitive material used to produce the cells and consisting for example of crystalline silicon, mono or triple-junction amorphous silicon, thin tellurium, cadmium, arsenic or gallium films, etc. Alternatively, fresnel lenses can be used, or an intermediate element (not shown in the drawings) for concentrating the sun's rays be interposed between the cover element 6 and the photovoltaic cells 8.

The integrated circuit 40, which is watertight, is able to perform a plurality of functions, and in particular of monitoring the external temperature in proximity to the tile, monitoring the solar radiation, automatic exclusion of any damaged or shaded photovoltaic cells 8, feeding data to the overall electronic control unit relative to non-operation and to the position coordinates of the non-operating component.

The tile of the invention constitutes a self-sufficient unit able to perform the necessary functions of electrical energy generation when the photovoltaic cells 8 are struck by sunlight, of automatic connection to other tiles on installation, and of controlling their regular operation.

Each tile is installed in substantially traditional manner, in the sense that their mechanical connection to the structural components of the building roof takes place tile by tile, thus determining the electrical connection between one and another tile.

In particular, laying the bottom tile of each row also determines the connection of the cables for transporting the generated direct current electrical energy into the building for its use. More particularly, the first tiles of each row have, at their ends, the exit for two cables, of positive and negative polarity respectively, which carry the direct current electrical energy into the building. Of the two cables which emerge from each first tile, one is connected to the first tile of the adjacent row, to form in this manner a series connection between the various rows. The two terminals of the series formed in this manner are connected to an inverter positioned inside the building, to convert the direct current into alternating current.

The various cables are also connected to the overall electronic control unit for transmitting the data originating from the integrated circuit 40 of each tile.

In laying the next tile, achieved by firstly laying the base 2 and then engaging its lower part 4 by coupling, this lower part surmounts a portion of the part 4 of the previously laid tile, hence causing the male connector 30 of this subsequently laid part 4 to connect into the female connector 34 of the previously laid part 4, and determining the electrical connection between the two adjacent tiles. During this step the closure of the seat 32 can be advantageously sealed by interposing a continuous gasket 50 between the two surmounted portions of the two adjacent parts 4.

After the entire row has been completed, the operator lays the adjacent corner, being careful to couple the appendices 12 of two adjacent bases and then stabilize the bases 12 in their correct position by engaging a single fixing screw through the aligned holes 13 in bases 12.

Other revisions and modifications to the modular photovoltaic element may occur to the artisans. For example, in lieu of interlocking teeth and seats for joining the cover to the hollow part, fasteners or adhesives may be utilized for joinder. The same holds true for cavities and appendices for securing a hollow part to the hollow part of an adjacent element in the same row. Consequently, the appended claims should be liberally construed, and should not be limited to their literal terms. 

1. A modular photovoltaic element for building roofs, comprising: a lower hollow structural part of plastic material, an upper convex cover element of material transparent to sunlight and fixed to said hollow part, at least one photovoltaic cell mounted on a support and housed in a cavity defined by said hollow part and said convex cover element, an integrated circuit for controlling the operation of said element, cabling associated with said photovoltaic cell, provided in said hollow part, a compartment which is separate from the cavity housing said photovoltaic cell, and which houses means for electrical connection to the adjacent modular element of the same row, partially superposed to cover said compartment, connection cables joined to watertight connectors positioned on the surmounting portions of adjacent hollow parts of one and the same row, said connectors being connected to said photovoltaic cell and to said integrated circuit, first mechanical means for connecting said cover element to said hollow part, second mechanical means for connecting said hollow part to the hollow part of adjacent elements of the same row, a base member adapted to connect said hollow part to an underlying roof.
 2. The modular element as claimed in claim 1, wherein said lower hollow part is fixed to the structural elements of the underlying roof by means of a base connectable to the base of the corresponding modular element pertaining to the adjacent rows.
 3. The modular element as claimed in claim 2 wherein the base is overall of tray shape, with the two longitudinal sidepieces projecting upwards, and from which at least two appendices extend downwards for its fixing to the roof structural elements.
 4. The modular element as claimed in claim 3, wherein said appendices have their lower end projecting outwards and presenting a profiled portion complementary to the profiled portion of the appendix pertaining to the base of the modular element of the adjacent row, said complementary portions being fixable to the underlying roof structure by a single fixing element.
 5. The modular element as claimed in claim 3, wherein each longitudinal sidepiece of the base comprises seats to be engaged by teeth provided in the overlying lower part
 4. 6. The modular element as claimed in claim 3, each longitudinal sidepiece of the base comprises appendices for centering the base of the adjacent modular element pertaining to the same row.
 7. The modular element as claimed in claim 1, said lower part presents a perimetral band consisting of a frusto-conical portion similar to that of a traditional tile and defining a sunken central portion housing at least one photovoltaic cell.
 8. The modular element as claimed in claim 7, wherein said photovoltaic cell is mounted on a support inclinable longitudinally and/or transversely.
 9. The modular element as claimed in claim 1, wherein the upstream end of the lower part is provided with a cavity housing a connector cooperating with a male connector provided in an appendix projecting lowerly from the downstream end of the lower part of that modular element pertaining to the same row, the two modular elements being partially surmounted such that the downstream end of the upper element is superposed on the upstream end of the lower element.
 10. The modular element as claimed in claim 9, wherein the two superposed ends of two adjacent elements comprise mutually cooperating appendices and cavities for their engagement and centering.
 11. (canceled)
 12. The modular element as claimed in claim 1, wherein said connectors are watertight and are connected via the cables to said integrated circuit, which is also watertight.
 13. The modular element as claimed in claim 7, wherein the bottom of said sunken central portion provided in the lower part includes aeration apertures.
 14. The modular element as claimed in claim 7, wherein said cover element is of frusto-conical shape and matches the frusto-conical perimetral band of the lower part.
 15. The modular element as claimed in claim 1, wherein the surface of said cover element comprises a plurality of solar ray concentration lenses.
 16. The modular element as claimed in claim 15, wherein said lenses are fresnel lenses.
 17. The modular element as claimed in claim 15, said lenses consist of elements separate from said cover.
 18. The modular element as claimed in claim 1, wherein said first mechanical means comprises seats along the edges of said hollow part and teeth in said cover element.
 19. The modular element as claimed in claim 1, wherein said second mechanical means comprises small cavities in the side of said hollow part that receive appendices on the adjacent tile. 